package com.example.demo.dao;

import com.example.demo.bean.NewsBean;
import com.example.demo.util.DBConnection;

import java.util.Date;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class NewsDao {
    DBConnection DBConn= new DBConnection();

    public List<NewsBean> getList(int page){

        Connection conn = DBConn.getConn();
        String sql = "select * from news limit "+(page-1)*10+",10";
        List<NewsBean> list = new ArrayList<NewsBean>();
        try {
            Statement statement = conn.createStatement();
            ResultSet rs = statement.executeQuery(sql);
            while (rs.next()){
                NewsBean newsBean = new NewsBean();
                newsBean.setNewsID(rs.getInt("NewsID"));
                newsBean.setNewsTitle(rs.getString("NewsTitle"));
                newsBean.setNewsContent(rs.getString("NewsContent"));
                newsBean.setNewsTime(rs.getString("NewsTime"));
                newsBean.setAdminName(rs.getString("AdminName"));
                list.add(newsBean);
            }
        } catch (SQLException e) {
            throw new RuntimeException();
        }
        return list;
    }

    /**
     * 添加新闻
     * @param news
     * @return
     */
    public int add(NewsBean news){
        Connection conn = DBConn.getConn();
        String sql = "insert into news value(null,?,?,?,?)";
        try {
            PreparedStatement pmst = conn.prepareStatement(sql);
            pmst.setString(1, news.getNewsTitle());
            pmst.setString(2, news.getNewsContent());
            pmst.setString(3, (new Date()).toString());
            pmst.setString(4, news.getAdminName());
            return pmst.executeUpdate(); // 执行添加 返回受影响的行数
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 更新功能
     * @param news
     * @return
     */
    public int update(NewsBean news){
        Connection conn = DBConn.getConn();
        String sql = "update news set NewsTitle=?, NewsContent=?, NewsTime=?, AdminName=? where NewsID=?";
        try {
            PreparedStatement pmst = conn.prepareStatement(sql);
            pmst.setString(1, news.getNewsTitle());
            pmst.setString(2, news.getNewsContent());
            pmst.setString(3, (new Date()).toString());
            pmst.setString(4, news.getAdminName());
            pmst.setInt(5, news.getNewsID());
            System.out.println("执行sql："+pmst.toString());
            return pmst.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return 0;
    }

    public int delete(int newsID){
        Connection conn = DBConn.getConn();
        try {
            String sql = "delete from news where NewsID=?";
            PreparedStatement pmst = conn.prepareStatement(sql);
            pmst.setInt(1, newsID);
            return pmst.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 统计新闻总条数
     * @return
     */
    public int count(){
        Connection conn = DBConn.getConn();
        try {
            String sql = "select count(*) from news";
            Statement statement = conn.createStatement();
            ResultSet rs = statement.executeQuery(sql);
            if(rs.next()){
                return rs.getInt(1);//cout查询返回一行数据 第一行第一列就是总条数
            }
        } catch (SQLException e){
            e.printStackTrace();
        }
        return 0;
    }
    public NewsBean getNewsByID(int ID){
        try {
        String sql = "select * from news where NewsID=?";
        NewsBean newsBean = new NewsBean();
        Connection conn = DBConn.getConn();
        PreparedStatement pmst = conn.prepareStatement(sql);
        pmst.setInt(1,newsID);
        ResultSet rs =  pmst.executeQuery();
        if (rs.next()){
            newsBean.setNewsID(rs.getInt(1));
            newsBean.setNewsTitle(rs.getString(2));
            newsBean.setNewsContent(rs.getNString(3));
            newsBean.setNewsTime(rs.getString(4));
            newsBean.setAdminName(rs.getString(5));
            return newsBean;
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return null;
};
